Manufacturing classification: lessons from organisational systematics and biological taxonomy,

37MANUFACTURING CLASSIFICATION

IntroductionIt is the belief of some scientists and statisticians that thedesire to classify objects and entities has resulted in avast waste of valuable scientific time. The need toproduce a scheme which will pigeon-hole an individualentity is natural to the human brain. Goodall[1], a notedbiologist, concluded that, “a preference for classificationis developed in childhood and persists as a habitual formof thought in adulthood”. The problem is not the desire toclassify, but the resultant multitude of schemes whichare based on a detailed understanding of the phenomenabut an extremely limited understanding of taxonomy.

The ability to develop a well-defined theoretical orempirical classification is a basic step in conducting anyform of scientific or systematic inquiry into thephenomena under investigation. In this article thephenomena under examination are discretemanufacturing systems and the purpose of theinvestigation is to identify attributes which will not onlyenable grouping, but will also help determine and predictthe laws and relationships which govern the operationalbehaviour of a manufacturing system.

The structure of this article is as follows:

● outline the need and usefulness of amanufacturing classification;

● derive taxonomic theories and rules frombiological taxonomy and organizationalsystematics;

● review existing manufacturing classifications toidentify essential attributes;

● list preliminary guidelines for the classification ofmanufacturing systems.

The purpose of a manufacturing classificationIn an amusing classification of classifications, Good[2]provided a list which suggested five purposes forperforming classification.

(1) for mental clarification and communication;

(2) for discovering new fields of research;

(3) for planning an organizational structure ormachine;

(4) as a checklist;

(5) for fun.

Most authors of manufacturing classificationsemphasize (1) and (2), but in the context ofmanufacturing change and improvement, point (3) is themost valid. Generally, any change initiative will includetwo stages, the ability to comprehend the situation inhand (problem definition) and with this knowledge,produce or identify an appropriate solution. These stagescan be performed using modelling and designmethodologies.

If a classification is linked to this change process, it ispostulated that groups of manufacturing systems can beformed based on similar technological and behaviouralattributes, and that there will exist an “ideal model” orsolution for the group. This group reference model willthen help reduce the time and costs associated withdeveloping solutions for individual companies withinthat group.

A second objective for producing a manufacturingclassification is based on the process of comparativestudy which enables the storage and retrieval ofinformation to facilitate the application ofgeneralizations point (4). This process enhances theinvestigators’ knowledge and understanding ofmanufacturing systems and will enable predictionsabout system behaviour.

Integrated Manufacturing Systems, Vol. 6 No. 6, 1995, pp. 37-48 © MCB University Press Limited, 0957-6061

Manufacturing classification:Lessons from organizational systematics and biologicaltaxonomyIan McCarthy

Classifications enhance knowledge and understanding and will enable predictions to be made aboutmanufacturing system behaviour

Classification scienceThis section provides an insight into the theories andmethods of taxonomy and classification. This isregarded as a necessity, as it would be improper todevelop a classification for manufacturing systemswithout understanding and applying the science ofclassification.

VocabularySystematics is the label given to the “science ofdiversity”[3]. Its application concerns the study ofsystems and the principles of classification andnomenclature. Systematics encompasses taxonomy andclassification (Figure 1), and is the logical starting pointfor understanding manufacturing systems for thepurpose of classification and modelling.

Taxonomy is the theory and practice of delimiting andclassifying different kinds of entities[4,5]). The processidentifies differences and attributes on which to base aclassification. Taxonomic differences withinmanufacturing systems include: operationalcharacteristics, levels of technology and flow structures.Thus, taxonomy is a process which determines theclassification scheme and the techniques used toconstruct it.

Classification is the development of a system or schemein order for investigators to arrange entities into taxa,based on the differences and attributes which were

identified from the taxonomic process[4,5]). Therefore,within a manufacturing context the taxonomy stagedefines the manufacturing system to be classified,identifies those attributes on which the classification willbe performed and selects an appropriate classificationtechnique, such as multivariate cluster analysis[6].

The classification stage is concerned with identifying asample of manufacturing companies, collecting attributedata by means of interviews and visits, and forming andvalidating groups of companies using a technique suchas cluster analysis. The relationship betweenclassification, taxonomy and systematics is shown inFigure 1. A classification scheme contains only onecategory of taxa, whereas a classification system containstwo or more categories of taxa[7].

Taxa (taxon is the singular) exist in all classificationsand can be any group of entities which are sufficientlysimilar to each other, while being sufficiently differentfrom entities in other sets. For example, organizationsare considered complex entities with schools,manufacturing companies and hospitals all being taxa(sets of similar entities).

Theoretical taxonomy is one type of methodology usedfor developing the classification. The theoretical type isbased on knowledge of the entity characteristics and thisis used to develop the classification. A shortcoming ofthis type as described by Carper and Snizek[8], is that theapplication data used in theoretically constructedtaxonomies have been collected primarily in support ofthe developed taxonomy. This means that when applyingthe classification, the investigators may inadvertentlyseek and collect data which support their taxonomy.

Empirical taxonomy is the second type of methodologywhich collects data on the entities (empirical evidence) onwhich to develop the taxonomy. Hence, the dataemployed are used to actually construct the empiricaltaxonomy, instead of supporting the classification as isthe case with theoretical taxonomy[8].

Biological taxonomyThe greatest application of taxonomy has been withinthe field of biological sciences (medicine, pharmacology,animal and plant sciences, zoology, etc.) to establishnames for organisms and a methodology for classifyingthem. Therefore, it would seem logical to review thetheory of classification within this discipline to establishlessons which could be useful for the development ofmanufacturing systems.

Mayr[9] reviewed the techniques used by zoologists andin summary, four theories of classification weredescribed:

38 INTEGRATED MANUFACTURING SYSTEMS 6,6

Taxa

Groups of manufacturing systemsRelevant nomenclature

Classification

Develop the system or schemebased on taxonomic proposalsCollect data on manufacturing attributesApply classification and develop groupsof manufacturing systems

Taxonomy

Theoretical/empirical approachNumerical/non-numericalIdentify the manufacturing system boundariesIdentify the attributes of the manufacturing system

Systematics

Manufacturing differences based on systems theoryMethodical approach

Figure 1. The concept of classification

(1) essentialism;

(2) nominalism;

(3) numerical taxonomy;

(4) cladistics

EssentialismBiologists believe that organisms have a hidden realitywhich can be defined, and that this reality dictates theorganism’s observed properties. This hidden reality isconsidered so influential that it determines how aproduct/object can be classified. Identifying thisessential attribute and basing a taxonomy on it is knownas “essentialism”. The benefit of essentialism is that itsimplifies the taxonomic task because only a fewattributes are considered. The main disadvantage is thatthe entity or object must be a totally analysable entity inwhich that essential attribute can be defined. As mostobjects are not totally analysable entities, biologistsdiscarded the theory of essentialism. However, theimportance of identifying and selecting essentialattributes was recognized, as this increases the validityof a classification.

NominalismThis theory suggests that all entities, includingmanufacturing systems, are different in some way andthat only individual entities exist. Thus, it is impossibleto classify anything truly and that belief and desire toclassify is an artefact of the human mind. With biologistsdeveloping classifications for birds, trees, plants, etc.they obviously felt that natural groups could be derivedand thus ignored this theory.

Numerical taxonomyIn the 1960s, the need for a more objective and scientifictaxonomy led to the development of numerical taxonomy.Developed by Sokal and Sneath[10], it is primarily anempirical method based on collecting data on thephenomena under study and then applying mathematicalprocedures such as cluster and discriminant analysis toform groupings.

CladisticsThis is defined by Fitch[11] as the process of definingevolutionary relationships between taxa using evidencefrom extant taxa. Originally formalized by Hennig[12],this a natural development of Darwin’s[13] theory ofnatural selection, which stated that the naturalgroupings of biological organisms were due to descentwith modification from common ancestors. At presentthis is the dominant taxonomic method. It should benoted that none of the manufacturing classifications

reviewed were developed on the principles of cladistics,but some do have an evolutionary nature, such as thedevelopment of mass production from craft production.

Organizational systematicsBusiness, management and organizational scientistshave also been keen developers of classifications.Developments include a business strategy classificationsystem[7], a voluntary association classification[14], acanning firm and farmers union classification[15] andgeneral organizational classifications[16-18]. Practitionersof organizational systematics were the first to realize thepotential benefits that biological taxonomy could offer interms of achieving a framework for classificationdevelopment which would result in the identification ofscientifically useful groupings.

Carper and Snizek[8] produced a critical review of pasttheoretical and empirical efforts with the aim ofestablishing a comprehensive framework. Chrisman etal.[7] examined business strategy classification and withreference to biological taxonomy, listed objectives forclassification and necessary attributes for a clas-sification system and its taxa. McKelvey[19] argued theimportance of biological taxonomy and developedguidelines for conducting multivariate classificatorystudies.

Considerations for a manufacturingclassificationThe following guidelines and principles are derived fromthe fields of biological taxonomy and organizationalsystematics. They have been translated into amanufacturing context with reference to attributeswhich are associated with manufacturing systems.

Essential attributes of the taxa (manufacturing system)This section lists five attributes which govern theappropriateness of the groups formed by classifications:

(1) Mutually exclusive. This means that it must not bepossible for any individual manufacturing systemto be assigned membership to more than onetaxon at any categorical level.

(2) Internally homogenous. Manufacturing systemswithin a taxon must be more similar to each otherthan they are to members of other taxa ifgeneralizations are to be valid.

(3) Collectively exhaustive. At each categorical level of aclassification system, every known manufacturingsystem must belong to an existing taxon.

(4) Stability. The taxa of a classification should not beaffected by empirical tests which use new or


alternative attributes. Reassignment of themanufacturing company should not be possibleunless attributes change within the company (i.e.a change in technology or a change from, make toorder, too, make to stock)

(5) Relevant naming. Mayr[5] suggested that the keyattributes in which the classification is basedshould be using for naming taxa. Bock[20] statedthat if the names are also based on commonacademic and business language this would aideffective communication.

Essential attributes of a manufacturing classificationThis section governs the components, construction andapplication of a classification.

Key attributesIn line with the theory of essentialism an effectivemanufacturing classification must be based on the keycharacteristics. Existing schemes have used technology,material flow, operational control, operational objectives,etc.

General classificationFor the purpose of manufacturing systems design, ageneral classification is more important forunderstanding and predicting the laws, functions andbehaviour which govern that system. Special purposeclassifications are limited in their application for broadfunctional studies.

Parsimonious classificationA parsimonious classification is one where the mostlikely evolutionary explanation is the one requiring theleast number of evolutionary steps. Researchers willexamine manufacturing systems and differentiate themfrom dissimilar manufacturing systems with the fewestnumber of taxa. A parsimonious classification must notinfringe other attributes such as internalhomogeneity[21].

Hierarchical classificationThis is the arrangement of manufacturing systems intoan ascending series of taxa. Hierarchical classificationsbegin at the bottom with individuals and end up at thetop with an all-embracing taxon. The different levels areknown as taxonomic ranks and all taxa existing in a rankare said to belong to the same taxonomic category[22]. Ahierarchical structure facilitates information retrieval,makes the classification easy to use and mostimportantly is an aid the comparative research betweenmanufacturing systems[23].

Timeless classificationCladistics is based on evolution and therefore theclassification should not be specific to a certain time

period. It should be capable of enabling systematicexamination of both past and future manufacturingsystems.

Review of existing classificationsTo help establish taxonomic guidelines and essentialattributes for a manufacturing classification,investigations have been made into system classificationand manufacturing classification. This provides athorough understanding of the phenomena and willenable lessons to be learnt for application into a systemtheory based classification.

Classification of systemsThere exist two base classifications of systems (Table I).Boulding[24] uses the criteria of complexity as theprincipal parameter, while Lievegoed[25] uses theconcepts of static, dynamism, openness and closedness.As the levels progress from 1 to 9, there is an increase insystems complexity. In terms of manufacturing systemsthere are comparisons between the Boulding andLievegoed classification criteria and the elements andattributes which constitute a manufacturing system. Thefirst three levels are made up of physical and mechanicalsystems and have direct relevance to manufacturingsystems types. The next three levels all deal withbiological systems and the remaining three levels are ofhuman, social and transcendental importance.

Comparing the Boulding classification to Lievegoed’swith reference to a manufacturing system there are clearparallels. Boulding’s framework system can beconsidered to be similar to the static element ofLievegoed’s typology and in terms of a manufacturingsystem relates to the static assemblage of elements suchas machines. The “clockworks system” refers to thesimple dynamics and motions of a dynamic system andis associated with manufacturing system flows such asmaterial and information. The “cybernetic system”relates to the control and maintenance of a system whichinteracts with the environment beyond its boundaries.This is Lievegoed’s “dynamic open system” and isassociated with the decision control which exists in amanufacturing system.


The “clockworks system” isassociated with manufacturing

system flows

Classification of manufacturing systemsAttempts to classify manufacturing systems have beendeveloped by production engineers and manufacturingsystems engineers. A review has been performed onthose classifications which are regarded as havingsubstance and the taxa labels are used regularly inengineering and common language (i.e. massproduction). The review (Table II) analysed the attributeson which the taxonomy was developed. This comparison(not classification) grouped the existing methods underfive general headings, as shown below:

(1) operational characteristics (job, batch, mass,project, intermittent, continuous, etc.);

(2) operational objectives (make to stock, make toorder, etc.);

(3) operational flow structures (flowlines, grouptechnology, VAT analysis, etc.);

(4) a detailed sub-classification of one of the above(batch, flowline);

(5) a combination of one of the above.These classification headings are supported byConstable and New[32] who stated that allmanufacturing systems can be defined by threecharacteristics: product structure, organizationalstructure; (flowline, cells, functional layout, etc.); and thenature of customer orders (make to stock and make toorder).

Operational characteristicsThe basis to classify by similar operating characteristicsrefers to the movement, logistics and control of thephysical resources required for production. This hasbeen comprehensively covered by Wild[26], whoclassified industry in two broad categories; continuous


Table I. Boulding’s and Lievegoed’s classification of systems

System typeLevel and level Description

Boulding

1 Frameworks Static

2 Clockworks The application of predetermined motions

3 Cybernetic system Self-regulating to maintain equilibrium

4 Open system Self-maintaining structure at cell level

5 Genetic societal system Self-maintaining structure at plant level

6 Animal system Mobility, teleological behaviour and self-awareness

7 Human system Self-awareness and the ability to utilize language and symbolism

8 Social system Consideration and content of messages, nature and dimensions ofvalue system, transcription of images into historical records, symbolization of human motion

9 Transcendatal system Ultimate, absolute and inescapable unkowables exhibiting systematic structure and relationship

Lievegoed

1 Static closed systems The relationship between selected factors does not change the system. Factors outside the boundary have no influence on factorswithin the boundary

2 Dynamic closed systems The time factor is included in this type of system and factors within the system change a certain way

3 Static open systems These systems have an input and an output. The input enters thesystem, reacts with the system and changes, and then exits the system. The system does not change

4 Dynamic open systems The same as the previous system but the system undergoes change while converting the input to the output. Every system that includes is by definition a dynamic open system

5 Dynamic open systems in Same as the previous system but the environment is changing and changing environments so is the input

process and the manufacture of discrete parts. Themanufacture of discrete parts was further subdividedinto three broad and overlapping categories, jobproduction, batch production, mass production Anothertraditional method for classifying manufacturingsystems based on operational characteristics issuggested by Johnson and Montgomery[27] whospecified three types, project, intermittent processes andcontinuous processes.

The main revelation with this classification was the taxa“project” which indicates a production effort where theproduct remains stationary throughout the productionprocess and workers, equipment and material arrive atthe site to perform assembly. Civil construction work andshipbuilding are the examples of project manufacturing.De Toni and Panizzolo[28] performed a classification ofproductive categories in order to overcome theambiguities concerning manufacturing classification.Six classifications were distinguished (individual,unique, intermittent, discontinuous, repetitive andcontinuous), along with the respective categories ofproductive plants (yards, laboratories, job shops andcells, etc.). Schmitt et al.[29] reviewed the classifications

based on operational characteristics, and stated that theyare not absolute because they are broad, have hybridsand exist on a linear continuum.

A combination system was suggested based on acombination of operational characteristics, rather than acombination of taxonomies. It is described as a generalproduction control system (PCS) which covers thesystems described and the hybrids between the systems.The PCS is based on three categories; task divisibility,production rate uniformity, and routing restrictions.These categories are represented on a three-dimensionalcontinuum, called a PCS cube.

Operational objectivesManufacturing companies and the productionmanagement system contained within them are createdfor a purpose, with that purpose in mind, the system willfunction and perform in a certain way. This is the basisfor the next group of classification techniques, whichattempt to define the affect the market variable has onthe operation of the manufacturing system and thencategorize each system accordingly.


Table II. A summary of existing manufacturing system classifications

Protagonist Taxonomic attributes Taxa Generic attributes

Wild[26] Quantity and variety of product, degree 4 Operational characteristicsof repetitiveness

Johnson and Montgomery[27] Relationship between resources and product flow 2 Operational characteristics

De Toni and Pannizzolo[28] Relationship between how the product is obtained 6 Operational characteristicsand how the production volume is obtained

Schmitt et al.[29] Operational characteristics Operational characteristics

Ingham[30]1 Observed sales and product range 8 Operational objectives

Wild[31] Operational objectives 4 Operational objectives

Constable and New[32] Nature of customer orders Operational objectives

Wild[33] Flowlines for mass production 6 Operational flow structures

Burbidge[34] Group technology 4 Operational flow structures

Burbidge[35] Material conversion 4 Operational flow structures

Frizelle[36] Material conversion 6 Operational flow structures

Aneke and Carrie[37] Flowline classification based on products, 10 Operational flow structuressequences and flow

Barber and Hollier[38] Production control complexity 6 Detailed operational characteristics

Woodward[39] Product complexity, operational objectives, 11 Combinationoperational characteristics

Burbidge[35] Material conversion and flow, and operational Combinationcharacteristics

Ingham[30] classified companies by their observed salesand the product range on offer. Four types ofmanufacturing company are suggested along with theirsub-categories. Wild[31] defined four basic types ofmanufacturing company according to the objective oftheir operating structure:

(1) from stock, to stock, to customer;(2) from source, to stock, to customer;(3) from stock, direct to customer;(4) from source, direct to customer.

The third criteria of the Constable and New[32]classification technique (nature of customer orders)supports this operational objective group. The techniquedefines two main categories “make to customer order”and “make for stock”. The first category is further sub-divided into jobbing production, contract work, batchproduction and call-off schedules.

Operational flow structuresAll manufacturing systems have an operationalstructure which links the elements of the system(products, resources and materials) and dictates thecharacteristics of the material flow in terms of itsconversion. This attribute differs from the headingoperational characteristics, in that it considers only thestatic/framework element of the manufacturing system(i.e. the layout). This group falls into three broadheadings of classification:

(1) flowlines;(2) group technology;(3) material conversion classification and VAT

analysis.Aneke and Carrie[37], and Burbidge[34] have produced acomprehensive review of headings (1) and (2), whileFrizelle[35] adequately covers heading (3).

Detailed classificationThe fourth heading of classification exists due to thedesire to produce a detailed and thorough classificationtechnique and represents the greatest level of objectivity.The following techniques have specialized in certainareas or characteristics of a specific classificationheading.

Detailed flowline classificationAneke and Carrie[37] produced a comprehensive flowlineclassification, more exhaustive than both the massproduction and group technology and flowlineclassifications. The classification produced ten flowlinetypes and is based on the following criteria:

● number of products;● number of operations required per product;

● sequence of operations divisible into: operationsof the same sequence, operations with variationsin the sequence;

● whether changeover is required from product toproduct or operation to operation;

● whether products are produced in batches or not;

● type of flow pattern.Burbidge[34] classified flowlines into three taxa, based onthe principles of group technology and plant layout:functional layout; group layout; and, line layout.

Detailed classification of batch systemsBarber and Hollier[38] developed a method of classifyingmanufacturing systems according to their productioncontrol complexity. This scheme resulted in six batchmanufacturing types and is based on a list of criteriawhich covers various aspects of production controlcomplexity. The criteria list relates closely to the criteriasuggested by Constable and New[32]:

● market/customer environment;

● product complexity;

● nature and complexity of manufacturingoperations;

● supplier environment;

● company structure and manufacturing policies.

Combination schemesAs part of a project to assess the impact of technologyupon the organization, Woodward[39] produced acomprehensive classification based on a broadcombination of manufacturing attributes as shownbelow.

● product complexity;

● production system (a combination of operationalobjectives and operational characteristics);

● production classification engineering (operationalcharacteristics).

This resulted in a classification where eleven productionsystems were identified.

A further development of Burbidge’s[35], materialconversion classification has led to a combinationtechnique, which includes flow type and organizationtype. The resulting classification is based on thefollowing criteria:

(1) Material conversion classification:

● process;

● implosive;

● square;

● explosive.


(2) Material flow types:● jobbing;● batch;● one of a kind;● continuous;● general (where two or more flow types exist).

(3) Type of organization:● process organization (process layout, not

process industry);● product organization (product layout):

continuous line flow (i.e. process industries);● group technology.

Comments on existing schemesAll of the manufacturing classifications discussedpresent a detailed understanding of the entity, but noclassification makes reference to, or applies the science ofclassification. A limited exception is where Barber andHollier[38] and Aneke and Carrie[37] utilize numericalclustering tools. Therefore, in terms of producing ascientific classification, which will provide optimalbenefits in terms of explaining and understanding thebehaviour of manufacturing systems, theseclassifications have various levels of deficiency. Anotherdrawback of the majority is the lack of objectivity. Somereferences are made to the desire to furtherunderstanding, but for what purpose or in what context,there is no reference. An assessment of themanufacturing classifications, against the taxa andclassification guidelines listed earlier is given.

When assessing the classifications against theguidelines listed for manufacturing taxa various levels ofsatisfaction are achieved. Most of the taxa produced aremutually exclusive and internally homogenous, due tothe thorough understanding of the entity by the authors.

This results in a clear focus on the attributes that areresponsible for distinguishing the manufacturingsystems. For example, make to stock and make to ordertype companies, are definitely discerned from flow typesor operational types. Taxa overlap occurs with the moregeneral classification such as Wild’s[26] job, batch andmass types. The ability for the taxa to be mutuallyexhaustive is achieved in the more detailed schemes such

as Barber and Hollier[38] and Aneke and Carrie[37],primarily because of the narrower scope and the desire toachieve a classification for one particular type ofmanufacturing taxon. The stability of the taxa producedby Johnson and Montgomery[27] is poor with themanufacturing types encroaching on Wild’s[26]. Thisalso occurs with the De Toni and Panizzolo’s[28]classification which provides additional and overlappingalternatives. Reassignment of manufacturing types alsotakes place among the classifications based onoperational objectives[30-32]. This is expected, due to thelack of a systematic and taxonomic approach and thelarge level of subjectivity concerned in analysing taxa.Also the levels of complexity play a part, withoperational objectives and operational characteristicshaving open and dynamic complexity. Classificationsbased on layouts and structures (static complexity)appear to satisfy the stability criteria of manufacturingtaxa.

Finally, the naming of the manufacturing types is weakwith no formal nomenclature or guidelines. Names arecreated, based on the author’s perception of the entityand the attributes used to formulate the taxa. Themanufacturing names tend to describe the attribute,rather than demonstrate its evolution. For instance thetaxon “mass” is a more appropriate name, than“Fordism”. Fordism reflects the inventor’s name, butprovides no information concerning the practices andbehaviour of this taxon.

Comments regarding the classification, rather than thetaxa produced, also have various levels of satisfaction.Many different attributes are used, with someclassifications using only three attributes (productionvolume, degree of repetitiveness and variety of productsWild[26] compared with the ten attributes used byBarber and Hollier[38]. This suggests that attributes arechosen based on the author’s perception of the hiddenrealities that govern manufacturing systems. “Essential”attributes must be used rather than prima faciebehavioural attributes, which are not exhaustive orcomprehensive. Frizzelle’s[36] descriptions of systemcomplexity are regarded as essential attributes. This isconfirmed by Hitomi[40] who provides four essentialattributes:

(1) Abstract. This is the collection and assemblage ofmanufacturing resources.

(2) Structural. This is system relationship and relatedto the interdependencies of the manufacturingresources. A collection of resources with norelationships is a group rather then a system.

(3) Transformational. This relates to the objectivityof the manufacturing system in terms ofconverting inputs into outputs.


Most of the taxaproduced are mutually

exclusive

(4) Procedural. This is the operational and dynamicaspect of manufacturing systems. The steps andcontrols required to achieve the transformationalaspect.

The number of classifications represented as a hierarchyare limited. A variety of representations are used fromthe PCS cube produced by Schmitt et al.[29], to therelationship tables produced by De Toni andPanizzolo[28] and Ingham[30], through to simple lists byBarber and Hollier[38] and Constable and New[32]. Atrue hierarchy representation is produced by Wild[26]and his classification of mass production systems.

Guidelines for the classification ofmanufacturing systemsEssential attribute selectionThe attributes used in previous classifications arevaried, broad, sometimes personal to the author and havea large degree of overlap. If a manufacturing system istreated as an open and dynamic operational system all ofthe attributes used have direct relevance to differencetypes of system complexity. Therefore, in terms ofselecting essential attributes which satisfy taxonomicguidelines, the following variants of complexity arerecommended.

Product complex ity. An indicator of the degree ofmanufacturing difficulty associated with the product(number of parts, number of connections, product varietyand volumes, etc.). A primary influence on structural anddynamic complexity.

Open complexity. The complexity of the environment thatthe manufacturing system must interact with(customers, suppliers, legislation, etc.). Also, a primaryinfluence on structural and dynamic complexity.

Structural complexity. An internal complexity relating tothe static/structural aspect of the manufacturing system.It is associated with hierarchy, size, flow structures, etc.Dynamic complexity. Related to structural complexity,but deals with the activity and time aspects (operational)of the manufacturing system. Describes the interactionbetween resources (material, machines, labour).

Classification developmentThe wide application of cladistics has resulted in thedevelopment of rules and principles. These rules concernthe operational principles of cladistics such as branchingand labelling. The rules are listed by Ross[41], and havebeen translated into a manufacturing system context,using system complexity as the core attribute.

The resulting 14 classistic guidelines are:(1) Focus on attributes central to manufacturing

system complexity.(2) Manufacturing systems having the greatest

overall similarity among their complexities willbe grouped together.

(3) Arrange the higher categories so that the familytree of manufacturing systems reflects theirevolution from past to present.

(4) Avoid too small or too large an aggregation ofgroupings at the higher levels, unless theevidence clearly indicates an extreme.

(5) Grouping within a category level (e.g. family,order, etc.) of the classification should be roughlyequivalent in overall similarity.

(6) Formal recognition of a group of manufacturingsystems should be accompanied by thedescription of its internal (operations) andexternal (market) environments.

(7) For each recognized branching of a newmanufacturing system away from an old one,identify at least one dominant environmentalforce that, when adapted to, would result in theattributes of the new form.

(8) Begin with the lineage’s which are most apparentand satisfy the objectives of the classification.

(9) Arrange the dendrogram (family tree) so thatsimilar manufacturing systems are adjacent toeach other.

(10) Give each manufacturing category a label,leaving room for future elaboration.

(11) Recognize that some forms of manufacturingsystems have evolved faster than others. Thus,more levels will be needed to in these lines toaccount for the increased levels of specializationand diversity.

(12) Use an italicized, hyphenated binominal name,with the genus name coming first and capitalizedand the species name second.

(13) All genus species labels will be in the singularand all higher category labels will be italicized,capitalized and given in the plural.

(14) Label a higher manufacturing class after adominant attribute differentiating that class fromothers at the same category rank.

In accordance with taxonomic hierarchy a preliminarydendrogram (Figure 2) has been produced to representmanufacturing category levels. The dendrogram doesnot suggest a correct or valid classification, but simplyprovides an illustration of how biological taxonomy canbe applied to manufacturing systems. The sub-tribe,genus and species level are a development of Wild’s[26]


classification. Each level is labelled and the terms usedare those usually employed in zoology. The dendrogramprovides a visual interpretation of the evolution ofmanufacturing systems with the vertical distancebetween levels representing time and the horizontaldistance between taxa representing the degree ofdifference.

The citation given to a taxa must act as a means ofreference and act as a vehicle for communication, itshould also indicate the rank of a taxon item (12) in thelist of cladistic guidelines. The codes of nomenclatureused by biologists, botanists and zoologists, require thatall scientific names be written in the Latin form.Nomenclature codes provide one form of regulation fornames of taxa above the rank of genus and another formof regulation for names of taxa below the rank of genus.

A preliminary example of a possible manufacturingclassification conforming to the codes of nomenclature

would be: Fabricator plurimi Ford. The citation includes“Ford” who is the “authority”, i.e. the first person tovalidly publish the name. Previous citations for this typeof manufacturing company were termed “Fordistcompanies” and “Fordism production”. Ford firstproposed this term in his 1926 article for theEncyclopaedia Britannica, Ford[42].

SummaryPrevious research into developing manufacturingclassifications has been based on a comprehensiveunderstanding of manufacturing companies, but with noreference to or application of the science of biologicaltaxonomy. This would be appear to be a majorshortcoming, which reduces the usefulness, stability andaccuracy of the classifications. Lessons have been drawnfrom biological taxonomy in an attempt to stimulatefurther investigations into this established problem


Organization

Industrialorganization

Manufacturingorganization

Discreteproduction

Batch production

Flow production

Transfer line

Processproduction

Projectproduction

Job productionMass production

Discreteflow lineFlow process

Assembly line

Quantityproduction

MechanizationLarge labour force

Kingdom

Class

Order

Family

Tribe

Genus

Species

Sub-species

Figure 2. Preliminary manufacturing dendrogram


based on the disciplines and rules regularly used bybiological scientists.

Classifications are based on knowledge, and asknowledge increases so will the validity of theclassification. As an investigator’s knowledge evolves, sowill the entities under study. In fact, a common statementwithin manufacturing is “the only constant is change”,derived from the need for continuous improvement. Thisleads to an inherent conflict between the need for aclassification which has stability and accuracy, versusthe inevitable evolution and change that manufacturingsystems are subjected to. Nevertheless, classification isthe only generally accepted system available for forminggroups.

Finally, the ability to undertake such research couldresult in a classification which is relatively accurate,stable, timeless and general. This scheme would greatlyenhance an investigator’s understanding ofmanufacturing systems and would increase the valueand accuracy of any predictions. An example of thebenefits that an appropriate classification could offer isthat, if accurate groups of manufacturing systems wereformed, an “ideal” model or solution for the group couldbe developed. This reference model would reduce thetime and costs needed to produce individual models orsolutions for manufacturing systems within that group.

References

1. Goodall, D.W,. “Vegetational classification andVegetational continua”, Angew. Pflanz (Wien) Festsch.Aich, Vol. 1, 1954, pp. 168-82.

2. Good, I.J., “Categorisation of classification”,Mathematics and Computer Science in Medicine andBiology, HMSO, London, 1965, pp. 115-28

3. Simpson, G.G., Principles of Animal Taxonomy,Columbia University Press, New York, NY, 1961, p. 7.

4. Mayr, E., The Growth of Biological Thought: DiversityEvolution and Inheritance, Harvard University Press,Cambridge, MA, 1982.

5. McKelvey, B., Organizational Systematics: TaxonomyEvolution, Classification, University of California Press,Berkeley, CA, 1982.

6. Everitt, B., Cluster Analysis, Gower, Aldershot, 1986.

7. Chrisman, J., Hofer, C. and Boulton, W., “Toward asystem for classifying business strategies”, Academy ofManagement Review, Vol. 13 No. 3, 1988, pp. 413-28.

8. Carper, W.B. and Snizek, W.E., “The nature and types oforganizational taxonomies: an overview”, Academy ofManagement Review, Vol. 5 No. 1, 1980, pp. 66-75.

9. Mayr, E., Principles of Systematic Zoology, McGraw-Hill,New York, NY, 1969.

10. Sokal, R. and Sneath, P., Numerical Taxonomy, thePrinciples and Practices of Numerical Classification,Freeman, San Francisco, CA, 1973.

11. Fitch, W.M., Cladistic and Other Methods: Problems,Pitfalls and Potentials. Cladistics: Perspectives on theReconstruction of Evolutionary History, ColumbiaUniversity Press, New York, NY, 1984, pp. 221-52.

12. Hennig, W., “Grundzuge einer Theorie derphylogenetischen Systematik”, Deutscher Zentraverlag,Berlin, 1950.

13. Darwin, C., The Origin of Species, Murray, London, 1859.

14. Gordon, C.W and Babchuk, N., “A typology of voluntaryorganizations”, American Sociological Review, Vol. 24,1959, pp. 22-3.

15. Emery, F.E. and Trist, E.L., “The casual texture oforganizational environments”, Human Relations, Vol. 18,1965, pp. 21-32.

16. Thompson, J.D., Organizations in Action, McGraw-Hill,New York, NY, 1967.

17. Perrow, C., Organizational Analysis: A SociologicalReview, Brooks-Cole, Belmont, CA, 1970.

18. Van Ripper, P.P,. “Organizations: basic issues andproposed typology”, in Bowers, R.V. (Ed.), Studies onBehaviour in Organizations, University of Georgia Press,Athens, GA, 1966.

19. McKelvey, B., “Organizational systematics: taxonomiclessons from biology”, Management Science, Vol. 24 No. 13, September 1978.

20. Bock, W., “Philosophical foundations of classicalevolutionary classification”, Systematic Zoology, Vol. 22,1973, pp. 375-92.

21. Quicke, D.J.L., Principles and Techniques ofContemporary Taxonomy, Chapman & Hall, London,1993.

22. Jeffrey, C., Biological Nomenclature, 3rd ed., Systematics’Association, Chapman & Hall, London, 1977

23. Ashlock, P., “An evolutionary’s systematists’ view ofclassification”, Systematic Zoology, Vol. 28, 1979,pp. 441-50.

24. Boulding, K.E., “General system thinking: the skeleton ofscience”, Management Science, 1956, pp. 197-208.

25. Lievegoed, B.C., Managing the Developing Organization,Basil Blackwell, Oxford, 1991, Ch. 2.

26. Wild, R., The Techniques of Production Management,Holt, Reinhart and Winston, London, 1971.

27. Johnson, L.A. and Montgomery, D.C., OperationResearch in Production Planning, Schedul ing andInventory Control, John Wiley & Sons, New York, NY,1974.

28. De Toni, A. and Panizzolo, R., “Repetitive andintermittent manufacturing: comparison ofcharacteristics”, Integrated Manufacturing Systems,Vol. 3 No 4, 1992, pp. 23-37.

29. Schmitt, T.G., Klastorin, T. and Shtub, A., “Productionclassification system: concepts, models and strategies”,International Journal of Production Research, Vol. 23No. 3, 1985, pp. 563-78.

30. Ingham H, Balancing Sales and Production: Models ofTypical Business Policies, Management Publications,1971, Chs 1-2.

31. Wild, R., Production and Operations Management,Cassel, London, 1989, Ch. 1.

32. Constable, C.J. and New, C.C., Operations Management:A Systems Approach through Text and Cases, JohnWiley & Sons, New York, NY, 1976.

33. Wild, R., Mass Production Management, the Design andOperation of Production Flowline Systems, John Wiley &Sons, New York, NY, 1972.

34. Burbidge, J.L., “Final report”, International Seminar onGroup Technology, Turin International Centre, Turin,1970.

35. Burbidge, J.L., The Principles Of Production Control, 4thEd, MacDonald & Evans, Plymouth, 1962.

36. Frizelle, G.D.M., “OPT in perspective”, AdvancedManufacturing Engineering, Vol. 1, January 1989.

37. Aneke, N.A.G. and Carrie, A.S., “A comprehensiveflowline classification scheme”, International Journal ofProduction Research, Vol. 22 No 2, 1984, pp. 282-97.

38. Barber, K.D. and Hollier, R.H., “The use of numericalanalysis to classify companies according to productioncontrol complexity”, International Journal of ProductionResearch, Vol. 24 No 1, 1986, pp. 203-22.

39. Woodward, J., Industrial Organization, Theory andPractice, Oxford University Press, 1980, pp. 22-49.

40. Hitomi, K., Manufacturing Systems Engineering (aUnified Approach to Manufacturing Technology andProduction Management), Taylor & Francis, Chichester,1979.

41. Ross, H., Biological Systematics , Addison-Wesley,Reading, MA, 1974.

42. Ford, H., “Mass production”, Encyclopaedia Britannica,13th ed., suppl., Vol. 2, 1926, pp. 821-3.


Ian McCarthy is a member of the Manufacturing Systems and Management Unit (MSMU) at the University of Sheffield.

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